Mousavi was raised in Khāmeneh, near Tabrīz, in northwestern Iran. He received an M.A. in architecture from the National University of Iran (later Shahīd Beheshtī University) in 1969, and he returned to that institution several years later as an instructor. During his tenure there Mousavi participated in the underground resistance movement to the regime of Mohammad Reza Shah Pahlavi.

Following the Iranian Revolution (1978–79), Mousavi served as the first political director of the Islamic Republican Party (IRP)—a prominent political organization until its dissolution in May 1987—and as editor in chief of the IRP’s official newspaper, Jomhūrī-ye Eslāmī. He briefly served as foreign minister during the hostage crisis with the United States (1979–81), in which militants seized 66 American citizens at the U.S. embassy in Tehrān, holding 52 of them hostage for more than a year (see Iran hostage crisis). He was subsequently appointed prime minister (1981–89), the country’s last before that post was abolished by constitutional amendment. Although Mousavi was favoured for the position by Ayatollah Ruhollah Khomeini, his tenure as prime minister was coloured by competition with Ali Khamenei, then president of Iran (and from 1989 the country’s supreme leader), who had strongly opposed his appointment. As prime minister, Mousavi is considered to have skillfully managed the country’s economy during the Iran-Iraq War (1980–88). In spite of great challenges—including the lengthy, costly war, a swiftly expanding population, and the strictures of a U.S. sanctions program—Mousavi managed to control inflation and ensure the reliable availability of essential items.

Following the abolition of the premiership in the late 1980s, Mousavi largely receded from the political spotlight. He dedicated himself to the arts and held several lower-profile positions within the government, including that of presidential adviser (1989–2005) to both Hashemi Rafsanjani and Mohammed Khatami. Mousavi also served as a member of the Expediency Council, the mediatory body meant to negotiate conflicts between the Majles (parliament) and the Council of Guardians (a body of jurists that reviews legislation and supervises elections). In 1998 he cofounded the Iranian Academy of the Arts in Tehrān and subsequently served as its president and the editorial director of Khiyāl (“Imagination”), the organization’s quarterly publication. In 1997 and again in 2005 Mousavi was urged by reformist groups to run for the presidency, but on both occasions he refused to do so.

2009 presidential election

After a hiatus of some 20 years, Mousavi returned to the political fore to run for president in the election of 2009. His campaign featured vocal criticism of Pres. Mahmoud Ahmadinejad and his policies, and he argued that the president’s controversial behaviour and rhetoric had damaged Iran’s image abroad. Economic concerns, increased personal freedoms, and the confrontation of corruption were also focal points of Mousavi’s campaign. He insisted that he would not suspend Iran’s nuclear enrichment program—a source of international controversy—which he underscored was for peaceful purposes.

In the months leading up to the election, former president Khatami, also a presidential candidate, to avoid splitting the reformist votes withdrew from the race and endorsed Mousavi’s candidacy. Although no Iranian president had yet failed to win a second term, observers considered the popular Mousavi a serious challenger to Ahmadinejad.

Voter turnout at the election in mid-June was estimated to reach record highs, a factor that some interpreted as favourable to Mousavi. Soon after the polls closed, Mousavi—who claimed he had been contacted by the interior ministry to inform him of his victory—announced that he had won the election outright by a large margin; shortly thereafter, however, officials made a similar announcement in favour of Ahmadinejad. Although Ahmadinejad insisted that the election had been fair and that his mandate had been broadened by the large turnout and the scope of his victory, his opponents alleged electoral fraud. Mousavi urged his supporters to protest the results, and, in the days following the election, demonstrations unfolded in the capital and elsewhere. Although Ayatollah Khamenei initially upheld the election results, he subsequently called for an official inquiry by the Council of Guardians into the allegations of electoral irregularities. The decision was quickly followed by an announcement by the Council of Guardians that the vote would be subject to a partial recount, a motion that fell short of the annulment the opposition had sought.

On June 19, following nearly a week of opposition demonstrations against the election results, Khamenei issued his first public response to the unrest: before a crowd of supporters at Friday prayers, he again backed Ahmadinejad’s victory and warned the opposition against further demonstrations. Along with Mehdi Karroubi, another reformist candidate, Mousavi attended neither Khamenei’s sermon nor a meeting convened by the Council of Guardians meant to provide the opposition candidates with an opportunity to discuss their concerns. Mousavi again called for an annulment and continued to urge supporters to demonstrate peacefully. Subsequent protests were greeted with increasing brutality as well as threats of further confrontation, and at a protest in Tehrān Mousavi announced that he himself was prepared for martyrdom.

On June 22 the Council of Guardians confirmed that 50 constituencies had returned more votes than there were registered voters (the opposition alleged that as many as some three times that number of constituencies had a turnout greater than 100 percent of eligible voters). Although the irregularities bore the potential to affect some three million votes, the Council of Guardians indicated that this would not change the outcome of the election itself. Following the completion of its partial recount, the council solidified Ahmadinejad’s victory by confirming the election results.